Despite losing star catcher and clean-up hitter Buster Posey as well as second baseman and No. 2 hitter Freddy Sanchez to season-ending injuries, the Giants were keeping their heads above water with excellent pitching and defense. Only the Phillies had prevented runs at a better clip than the Giants on the fateful day general manager Brian Sabean pulled the trigger on a deal that sent top pitching prospect Zack Wheeler to the Mets for right fielder Carlos Beltran.

Beltran was supposed to replicate Posey's production in the middle of the lineup over the final two months of the season to give the Giants a chance to defend their World Series title. When he was healthy enough to play, Beltran held up his end of the bargain by hitting .323/.369/.551 down the stretch. Unfortunately, injuries derailed the season for Beltran and the rest of the team.

As if losing Posey and Sanchez wasn't enough, Beltran then went on the shelf for 13 games with a wrist strain. Pablo Sandoval battled a shoulder injury that prevented him from hitting right-handed late in the year after missing 41 games earlier in the year with a broken hamate bone.

Closer Brian Wilson threw only five innings over the final two months due to an elbow problem. Set-up man Sergio Romo missed 16 games with elbow inflammation. Finally, to add insult to a series of injuries, Jeremy Affeldt suffered a season-ending injury trying to separate frozen hamburger patties.

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Losing Posey to injury was the first in a series of devestating injuries for the Giants in 2011.

The injuries—combined with poor performances from several able-bodied players including 2010 heroes Aubrey Huff, Cody Ross and Andres Torres—led to a two-month collapse directly after the Beltran trade. The Giants were swept in a three-game road series in Cincinnati to close out July—sending them into a tailspin from which they would never recover.

After winning their first game with Beltran in the fold, the Giants went 25-32 the rest of the way to finish eight games behind the Diamondbacks in the NL West. Beltran bolted in free agency, and the Giants couldn't even get draft pick compensation due to a provision in his contract that prevented him from being offered arbitration.

Meanwhile, Wheeler is now rated as one of the best prospects in the game with a fastball that reaches 97 MPH, a nasty curve and a developing changeup. He looked dominant in his first outing of the spring on Saturday, and he could make his professional debut this season. With Tim Lincecum and Barry Zito set to hit free agency after this season, Wheeler would be set to take over a rotation spot next season if the Giants hadn't dealt him.

Zack Wheeler settling down and gets a big strikeout on a fastball. Running it up to 97 mph according to TV crew.

However, the now infamous trade wasn't a failure just because Wheeler is now developing into a frontline arm, and Beltran didn't carry the Giants into the postseason in 2011. The Giants were desperate for offense, and Beltran was the best bat available. They had a title to defend and acquiring an All-Star caliber middle-of-the-order bat like Beltran was their best shot to make up for the loss of Posey.

The one possible quibble with the trade that doesn't get mentioned very often is that the Giants appeared to choose to insert Wheeler into the deal instead of a top position player prospect like Gary Brown. Sabean said at the time of the trade (via Henry Schulman of the San Francisco Chronicle),

We didn’t think [Zack] Wheeler was going to impact our situation in the immediate future. Quite frankly, it’s our job to find another Wheeler or develop another Wheeler. Once we decided we weren’t going to part with position players, we decided to go down this path.

While he didn't come out and say that the Giants decided to deal Wheeler over Brown, he implied it somewhat by saying that the organization had concluded not to deal any position players, and Brown was the top position player in the system at that point. However, it's also possible that the Mets wouldn't have made the deal with Brown inserted for Wheeler.

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The Giants didn't want to deal a top position player like Gary Brown back in 2011.

It's important to note that Brown's stock was much higher at the time of the deal than it is now. He finished 2011 with a .336/.407/.519 batting line, 53 steals and the reputation of being a potentially elite defensive center fielder. He entered last season as Baseball America's 38th best prospect, only three spots behind Wheeler.

Brown's stock has dropped significantly after a down year at Double-A Richmond, while Wheeler's star has risen drastically after a big year in the upper levels of the minor leagues. Yet prospects are unpredictable, and next year at this time the Giants might be happy to have Brown over Wheeler depending on how both prospects perform this season.

In the end, it's not fair to evaluate the trade in hindsight. At the time of the deal, there was no way to predict that Beltran and the rest of the roster would be besieged by injuries. There was no way to know that Wheeler would take a leap forward, while Brown would drop off in 2012.

The cost of trying to defend a championship was high in parting with Wheeler. Yet if the Giants had stood pat and then collapsed down the stretch, pundits would have been hollering at Sabean for not doing everything in his power to get the Giants back into the postseason.

The 2011 season started to collapse with the three-game sweep in Cincinnati. Thus, it was only fitting that the 2012 season took off with a three-game sweep in the NLDS over the Reds back in Cincinnati to propel the Giants to their second World Series championship in three years. It was even more fitting that Beltran's new team, the St. Louis Cardinals, were the opponent the Giants knocked off next to advance to the World Series.

The Beltran trade didn't help the Giants defend their title in 2011. Two years later, the Giants are back on top of the world anyway.